This is not 1st time when Pakistani Black hats attack on any country cyber space. Most likely, the attacker hasn't actually breached Yahoo! or Google severs. Instead, he gained access to DNS servers and altered the records to ensure that all visitors of msn.ug or Google.ug would be redirected to his defacement page.

Pakistani hackers stepped ahead and defaced all these large scale websites, owned by top brands. All the hacks appear to be affecting the .ug and .com.ug domains, suggesting this could be a DNS attack.